libhector_gazebo_ros_magnetic.so : magnetometer measurements drifting

[PizzocaroSolomon]

Hi!
first of all I want to thank you for the grate work that you shared with us :)

I added in my Gazebo model the "libhector_gazebo_ros_magnetic" plugin to have magnetometer measurements.
I noticed that the measurements are drifting rapidly over time. I wonder if it's a problem of incorrent I'm setting of the plugin and the magnetic field components or is something inside the plugin code.

This is how I'm including the plugin in my .sdf file :

...
<plugin filename="libhector_gazebo_ros_magnetic.so" name="magnetometer">
    <robotNamespace>/</robotNamespace> 
    <bodyName>base_link</bodyName>
    <topicName>imu/mag</topicName> 

    <updateRate>50</updateRate> 
    <magnitude>47.71</magnitude> 
    <referenceHeading>0.0</referenceHeading> 
    <declination>3.0</declination> 
    <inclination>60.0</inclination> 

    <offset>0.0 0.0 0.0</offset> 
    <drift>0.0 0.0 0.0</drift> 
    <driftFrequency>1 1 1</driftFrequency> 
    <gaussianNoise>0.0 0.0 0.0</gaussianNoise>
 </plugin>

In my .world file these are the environment info:

<spherical_coordinates>
      <surface_model>EARTH_WGS84</surface_model>
      <latitude_deg>45.22159023006877</latitude_deg>
      <longitude_deg>11.993919883456432</longitude_deg>
      <elevation>0</elevation>
      <heading_deg>0</heading_deg>
 </spherical_coordinates>

  <gravity>0 0 -9.81</gravity>
  <magnetic_field>6e-06 2.3e-05 -4.2e-05</magnetic_field>